Balanced rotary valve



(No Model.)

T. H. PARVIN.

BALANCED ROTARY VALVE.

No. 394,992. 3 Patented Dec. 25, 1888.

N. PEI'ERi Phnlo-Lilllagrnphlr. Washington D. C.

NITE STATES ATENT Grates.

THOMAS HENRY PARVIN, OF (AR-MI, ILLINOIS.

BALANCED ROTARY VALVE.

SPECIFICATION forming part of Letters Patent No. 394,992, dated December 25, 1888.

Application filed A ril 14, 1888. Serial No. 270,694. (No model.)

To all whom it may concern.-

Be it known that I, THOMAS HENRY PAR- VIN, a citizen of the United States, residing at Carmi, in the county of Vhite and State of Illinois, have invented certain new and useful Improvements in Balanced Rotary Valves, of which the following is a specification.

This invention relates generally to steamvalves, and particularly to such valves as are commonly known as balanced rotary valvesthat is to say, to that class of valves wherein the valve proper is composed of two wings carried by a single stem and adapted to be oscillated to move the wings to close or open the steam-outlets.

In that class of engines emplqviug a Sawyer valve for throttling the steam, and wherein the load is being continually taken off and put onto the engine, it is preferable to so throttle the steam when the load is removed that sufficient steam be admitted to the engine to run it slowly, and hence obviviate the necessity of continually starting up the engine from a state of rest. A "alve adapted to permit this operation of the engine has heretofore been proposed; but in such structure a separate by-pass was employed for the passage of the fluid around the valve proper. In the present improvements this is effected by providing the valve with an eductor-chamber surrounding the valve-chamber and forming an auxiliary port through the casing of the valve-chamber, so that a small quantity of steam may be constantly permitted to pass to the engine after the throttle has been closed to keep the engine in motion. In some instances and in the preferable construction I provide this auxiliary port with a valve which when seated to close said port permits the valve proper to be used as a positive throttle-valve, entirely cutting off the further admission of steam to the engine.

The accompanying drawings illustrate a valve provided with my improvements, in which Figure 1 is a side elevation thereof; Fig. 2, a central verticalsection of the same, taken on the line 2 2 of Fig. 3, certain portions being shown in elevation; and Fig. 3, avertical cross-section taken on the line 3 3 of Fig. l, certain portions being shown in elevation.

A The valve-casing A may be of the usual construction, adapted to be interposed between the ends of two pipes, 12 c, constituting a steamconduit, B, from the boiler to the engine, and provided with a valve-chamber, H, and a circumferential eduction-chamber, I. The pipe b opens into the valve-chamber I-I between the wings (Z (Z of a valve, 0, and the pipe 0 is in connection with the eductionchamber I, and by two ports, '1', of equal size, with the valve chamber ll upon opposite sides thereof, as in Fig. 3.

The valve-chamber is circular in form, providing a similarly-shaped seat for the valve C, so as to permit the latter to be oscillated therein. Its wings (Z are formed integral with one another and separated a distance apart by a connecting-web, f, of considerably less extent than the wings, so as to permit the steam occupying the valve-chamber to exert its pressure upon the inner surfaces of the wings. From the valve extends a stem,

. D, projecting through a central opening in a screw-cap, E, which closes the end of the chamber and through a'stuffingbox, F, formed in said cap, which is closed by another cap, G, said stem being provided on its outerend with a handle or other means of turning-it to operate the valve. A

The wings cl of the, valve in practice will be made of equal size and a little wider than the openingsi, which they control, so as to properly close them when the valve is turned for that purpose, as indicated in the drawings, and thus the steam-pressure upon the inner side of the wings and any suction on the chamber I side thereof through their ports i will be equally balanced. The effect of this equality in the area of the balanced wings, as before stated, is to counteract the suction in the pipe 0 and chamber I, caused by any movement of the engine after the steam-supply is shut off therefrom or otherwise, and to balance said suction equally and enable the valve to be easily oscillated to open the valve during the continuance of said suction. I find in practice that by thus equalizing the area of the balanced wings d all tendency of the valve to stick is obviated;

that it acts as elt'ectually with steam at high pressure as it does at low pressures, and that it responds quickly upon a very slight exercise of power to open it while the partial vacuum exists in the steam-pipe between the engine and the valve.

The eduction-chamber I completely surrounds the valve-chamber, and the wall of the latter is provided with an auxiliary port, 122, through which steam may pass to the engine after the valve has been moved to close the ports 1'. This auxiliary port will only be of such size as to admit steam suflicient to run the engine without any load, and hence prevent it coming to a state of rest upon closing the valve. In order, however, to enable the valve to be used as a positive throttle, I prefer to provide the auxiliary port on with a valve, L, adapted to be moved to its seat to close said port.

As shown, this valve consists of a screwthreaded stem passing through. a similar threaded hub on the valve-casing, having a hand-piece, n, to turn it to open and close said port. I also prefer to employ this stem as an oil-conduit, so that oil may be fed into the valve to keep it well lubricated and also, in a measure, permit the steam to carry oil to the valve and cylinder of the engine. For this purpose the valve L is provided with a central passage, 0, extending en tirely through it and connecting with a closed oil-reservoir, p, carried by the valve, as shown. Thus in any position of the valve L, whether the valve be used as a throttle or as a Sawyer Valve, oil may be conveniei'itly fed thereto.

\Vhat I claim isl. The combination of a valve-chamber provided with eduction-ports i, a valve controlling said ports, an eduction-cham'ber surrounding the valve-chamber, and an auxiliary port in the casing of the valve-ehamber and in direct communication with. said eduction-chamber, substantially as described.

2. The combination of a valve-chamber provided with eduction-ports 1', a valve controlling said. ports, an eduction-chamber surrounding the valve-chamber, an auxiliary port in the casing of the valvc-chamber and in direct communication with said eductionchamber, and a valve controlling said auxiliary port, substantially as described.

The combination, with a valve-chamber provided with an eduction-port and a valve controlling said. port, of an auxiliary port, in, and valve L for controlling the same, provided with a central oil-passage, substantially as described.

4-. The combination, with a valve-chain])er n'ovided with an eduction-port and a valve controlling said port, of an auxiliary port, in, and a valve, L, for controlling ihe same, h ing a central oil-passagc and an oil-reservoir carried by said valve, substantially as described.

Intesti mony whereof I have signed my name to this specification in the presence of two subscribin witnesses,

TI 1 OMAS ll ENRY PARVIN. lVitncsses:

JOHN C. DINNEL, FRED DETRov. 

